Estudo avaliativo da resistência ao impacto de um aço SAE 4140 após tratamento termoquímico de cementação

Abstract

Steel is one of the most versatile products in the world, being used from food packaging to the manufacture of large structures or civil shipbuilding. The SAE 4140 steel is used for processing with average hardenability on the chromium and molybdenum, used in the manufacture of various mechanical components such as bearings, cylinders, gears, hydraulic shafts, drilled shafts, rings, nuts and bolts, rods, where you want a good combination of average strength and fracture resistance and also has high resistance to fatigue. Thus, the main objective of this study is to examine the impact resistance of an SAE 4140 steel subjected to thermochemical treatment of carburizing and quenching and tempering treatments after considering the fixed temperature and time varied treatment. By analyzing the images made with the optical microscope of the metallographic samples with and without treatment thermochemical treatment, for checking the change of the microstructure to further evaluate the mechanical resistance through impact tests (Charpy test) and hardness. Thus, through the analysis to only a hardened piece obtained interesting results and condition 2 achieved the best results of hardness.